While squeeze bottle type sprayers have been used for many years, such sprayers were largely displaced for a period of time by spraying apparatus using a pressurized can. More recently, due to the very high cost of a product purchased in a pressurized can, in addition to the possible harm to the atmosphere by fluorocarbons used as the propelling gas, squeeze bottle type sprayers and manual pump sprayers are becoming quite prevalent.
The products dispensed in the form of a spray range extremely widely from products as easily atomizable as water, and as difficult to atomize as a reasonably heavy petroleum or a vegetable oil. If a product is to be sprayed from a pressurized can, there is sufficient force available that mechanical means can be used to break up the liquid droplets to produce a relatively fine spray; however, when the force is to be supplied manually, either by squeezing a bottle or using a pump or a trigger spray or the like, it is much more difficult to achieve a very high degree of atomization for products such as petroleum or vegetable oil.
For many years, squeeze bottle type sprayers have utilized a dip tube extending into the liquid and connected to a passage that leads directly to the spray orifice. Air is conveyed through another passage and caused to impinge on the stream of liquid in an effort to break up the liquid into droplets, and to disperse the liquid into the desired spray pattern. When the liquid has not been sufficiently atomized, or sufficiently dispersed, efforts have been made to cause additional swirling of the air and liquid at the point of mixture, but the basic technique has remained about the same.